With the development of technology, mobile phones, digital cameras, tablet PCs, notebook computers and other portable electronic devices become more and more popular. The portable electronic devices are intended for personal use, with certain privacy. The information stored in the portable device such as phonebook, photos, personal information, etc., are privately owned. If the electronic device is lost, these data may be accessed by other people, causing unnecessary loss. Even though there are several ways using password to protect the electronic device from being used by the other people, the password may be easily to be spread or cracked, which lowers the security. Moreover, the user needs to remember the password so as to use electronic devices. If the user forgets the password, troubles would be brought to the user. Hence, personal fingerprint identification is utilized to achieve the purpose of personal identification, for enhancing the data security.
For example, the electronic device (e.g., a smart phone or a tablet computer) may verify the identity by fingerprint recognition. After the identity verification is accomplished, the electronic device may enter into a normal operation from a sleep mode. In general, when the electronic device is in the sleep mode, the display panel of the electronic device may be locked or temporarily shut down (off). However, when the electronic device is in the sleep mode, if the user likes to press his/her finger on the display panel (to input his/her fingerprint) to perform identity verification, the display panel is all dark since it is temporarily shut down, and the user do not know where to press the finger to input the fingerprint, which lowers the user convenience.